Subject: bug#64642: 29.0.92; Native compiler doesn't compile dynamically bound functions.

From: Alan Mackenzie <[email-masked]>
Date: Sat, 15 Jul 2023 09:38:13 +0000

Hello, Emacs.

In the Emacs 29 pretest version (or the master version):
(i) emacs -Q
(ii) C-x b foo.el <RET>
(iii) M-x emacs-lisp-mode <RET>
Don't set lexical-binding in this buffer.
(iv) Enter a function called foo:
    (defun foo () "foo doc string"
      (lambda (bar) "lambda doc string" (car bar)))
(v) With point after the function, evaluate it with C-x C-e.

(vi) M-: (native-compile 'foo)
This signals an error, native-compiler-error-dyn-func.  This is a bug.

#########################################################################

The immediate cause of the bug is in the version of
comp-spill-lap-function which processes named functions (comp.el).
Unlike the other version of the cl-defmethod (which processes lambda
functions), there is no code for dynamic functions here.

If the intention is not to process dynamic functions, this should be
indicated by an error message rather than a signal.  Personally, I feel
that dynamic functions ought to be handled in Emacs-29.

Fixing this bug should be relatively straightforward, since it should
only involve copying and adapting the corresponding code in the lambda
version of comp-spill-lap-function.

-- 
Alan Mackenzie (Nuremberg, Germany).